Yieldable impeller for two-stage snow blower

ABSTRACT

A paddle wheel impeller, for, e.g., the second stage of a two stage snow blower, has relatively thick blades of rubber-like material. To prevent the blades from being flexed so sharply as to cause cracking at their front faces, each has behind it a rigid backing member that flatwise engages the rear face of the blade adjacent to its radially inner edge, thence curves rearwardly and radially outwardly away from the normal plane of the rear blade face.

United States Patent 1191 Kamlukin et a1.

1451 Apr. 23, 1974 YIELDABLE IMPELLER FOR TWO-STAGE SNOW BLOWER [75]Inventors: Igor Kamlukin, Mequon; Michael T.

Prevost, Cedarburg, both of Wis.

[73] Assignee: Simplicity Manufacturing Co., Inc.,

Port Washington, Wis.

[22] Filed: Nov. 22, 1972 [21] App]. No.: 308,841

Related US. Application Data [63] Continuation of ser. No. 106,121, Jan.13, 1971,

abandoned. I

[52] US. Cl 37/43 D, 302/38, 56/294 [51]- Int. Cl E0lh 5/00 [58] Fieldof Search 302/38, 49; 239/214, 223, 239/224; 37/43; 56/249, 294, D16.19, DlG. 20; 15/230, 230.19

[56] References Cited UNITED STATES PATENTS 2,715,246 8/1955 Van Doorn302/49 X 2,734,328 2/1956 Wood 56/DlG. 20 3,021,661 2/1962 Couberly56/294 X 3,678,671 7/1972 Scarnato et a1 56/294 3,321,851 5/1967 Fisher37/43 R X 3,580,351 5/1971 Mollen 37/43 E 3,334,429 8/1967 Price 37/43 R2,104,881 1/1938 McLemore 302/49 X 2,984,872 5/1961 France 302/49 X2,903,302 9/1959 Ross 302/49 Primary Examiner-Ernest T. Wright, Jr.Assistant Examiner-Eugene H. Eickholt [5 7] ABSTRACT A paddle wheelimpeller, for, e.g., the second stage of a two stage snow blower, hasrelatively thick blades of rubber-like material. To prevent the bladesfrom being flexed so sharply as to cause cracking at their front faces,each has behind it a rigid backing member that flatwise engages the rearface of the blade adjacent to its radially inner edge,thence curvesrearwardly and radially outwardly away from the normal plane of the rearblade face.

2 Claims, 3 Drawing Figures This application is a continuation of ourcopending application Ser. No. 106,121, filed Jan. 13, .1971, nowabandoned.

This invention relates to paddle wheel impellers for propulsion ofnon-fluid materials, and refers more particularly to an improved paddlewheel such as that used for the second stage of a two stage snow blower,capable of accommodating pieces of hard material such as stones andchunks of ice that may be mixed with softer material upon which thepaddle wheel normally operates.

One means for effecting propulsion of relatively soft homogeneousmaterials is a paddle wheel impeller rotating in a chamber having inletarid outlet openings. Various fluid pumps employ this principle, but itis also applicable to the propulsion of non-fluid semi-solid materialssuch as snow and of particulated solid materials such as sand.

The second stage of a two-stage snow blower offers an example of apaddle wheel impeller used for the propulsion of non-fluid materials.Such a snow blower is commonly powered by a single-cylinder gasolineengine, and is adapted for clearing sidewalks, driveways, parking areasand the like.

A two-stage snow blower has an auger which rotates on an axis thatextends transversely to the normal direction of motion of the machineand has a forwardly opening hood embracing the auger. Behind the hood isa compartment in which a paddle wheel impeller rotates. The paddle wheelcompartment is so communicated with the hood that snow is delivered tothe paddle wheel by the auger. The paddle wheel throws the snowupwardly, discharging it'through a spout that opens from the top of thepaddle wheel chamber.

In the operation of any such snow clearing machine it often happens thatpieces of harder material, such as ice, stones and wood, are picked upalong with snow. When these enter the paddle wheel chamber they can jamthemselves between the blades of the paddle wheel and the adjacent wallsof the chamber.

Heretofore the paddle wheels of snow blower second stages have had rigidblades, and any jamming of a stone or the like between a paddle bladeand the chamber wall tended to stall the engine by which the machine wasdriven. Clearing the jam was troublesome and difficult because theinterior of the paddle wheel compartment was accessible only through therelatively small diameter spout outlet or through the opening thatcommunicated the chamber with the hood, which opening was partiallyblocked by the auger. In some cases a jam could also result in damage tothe paddle wheel blades or to the compartment wall.

Having in mind these objectionable characteristics of prior paddle wheelimpellers for two-stage snow blowers, it is a general object of thisinvention to provide such an impeller that is substantially non-jamming,and which can accommodate chunks of hard material by reason of the factthat its blades are made of resiliently flexible material.

The mere provision of resiliently flexible blades does not completelysolve the problem, however. In the first place, the blades must havesome degree of rigidity and stiffness, along with their flexibility, forif they are too floppy they will not be capable of exerting the forcerequired to throw snow to a substantial height above the machine. Toachieve the necessary stiffness without impairing flexibility, eachblade must therefore have substantial thickness.

If a resilient blade is supported along one edge thereof and is causedto flex rearwardly by a force that is applied to it at some distancefrom that edge, the blade will normally bend to a small radius curvaturedirectly adjacent to the zone of its support, while the remainder of theblade that is spaced outwardly from that edge will be bent to arelatively large radius. In the zone of the small radius bend theportion of the blade material that is adjacent to the outer radius ofthe bend is placed under a tension that isapproximately in inverserelationship to the radius of the bend and in direct relationship to theblade thickness. With a relatively thick blade, such as must be used fora snow blower paddle wheel, the fibres of the material that are adjacentto the front blade face are thus stretched to several times their normallength by a small radius bend, and hence they can be easily strained tothe breaking point. When this happens, a crack begins to develop at thefront face of the blade, near the line of its support. I

With additional and repeated rearward flexing of the blade this crackrapidly deepens until the blade fails.

. With these considerations in mind, it is another object of thisinvention to provide an impeller wheel of the character described havingrelatively thick, and therefore fairly stiff, blades of resilientlyflexible material, and having means for preventing its blades frombending about a relatively short radius when they flex, althoughpermitting them to flex rearwardly to the extent necessary to yieldinglyaccommodate pieces of hard material.

Thus it is the general object of this invention to provide a paddlewheel that is particularly well suited to serve as the second stageimpeller of a two-stage snow blower, which paddle wheel is substantiallynonjamming in the presence of large chunks of hard material and iscapable of a very prolonged useful life without replacement of itsblades.

With these observations and objectives in mind, the manner in which theinvention achieves its purpose will be appreciated from the followingdescription and the accompanying drawings, which exemplify theinvention, it being understood that changes may be made in the specificapparatus disclosed herein without departing from the essentials of theinvention set forth in the appended claims.

The accompanying drawings illustrate one complete example of theembodiment of the invention constructed according to the best mode sofar devised for the practical application of the principles thereof, andin which:

FIG. 1 is a front perspective view of a two-stage snow blower embodyingthe principles of this invention;

FIG. 2 is a fragmentary view on an enlarged scale of the snow blowershown in FIG. 1, partly in side elevation and partly in longitudinalsection; and

FIG. 3 is a perspective view of the paddle wheel of this invention.

Referring now to the accompanying drawings, the numeral '5 designatesgenerally a two-stage snow blower which illustrates one application ofthe principles of this invention. The snow blower 5 is of the type usedfor clearing sidewalks, driveways and the like, and is powered by asmall gasoline engine 6 that is mounted at the rear of the machine, overa pair of wheels 7 which may be drivingly connected with the engine in aknown manner.

At its front the snow blower has a forwardly opening hood 8 in which anauger 9 is rotatable on a horizontal axis that extends transversely tothe normal direction of movement of the machine and substantiallyparallel to the axis of the wheels 7. Shoes or skids 10 on each side ofthe hood, at the bottom thereof, are adapted to engage the surface andto cooperate with the wheels 7 in carrying the machine for its forwardmovement. Handles 11 on the machine, projecting rearwardly therefrom,enable an operator walking behind the machine to guide it.

As is well known, the auger 9 is drivingly connected with the enginethrough a suitable transmission (not shown). As the auger rotates,helical flights 12 on it propel snow upwardly and laterally inwardly,towards an opening 13 in the upper rear portion of the hood, midwaybetween the sides thereof. It will be understood that the flights 12 ateach axial side of the auger are pitched oppositely to those at theother side thereof in order to effect such. laterally convergentmovement of 'the snow, and that the flights terminate short of thecentral portion of the auger.

Behind the hood there is a generally drum-shaped second stage chamber 14in which a paddle wheel impeller 15 is rotatable about an axis parallelto that of the wheels and the auger. The opening 13 cornmunicatestheinterior of the hood with the impeller chamber 14 and is so shaped andlocated that the blades 16 of the paddle wheel can pass between theflights of the auger as the blades move through a forward portion oftheir orbits, to receive the snow that is driven toward the opening 13by the auger.

The chamber 14 fits the paddle wheel impeller rather closely, so thatthe chamber and the impeller in effect cooperate to provide a pump thathas the opening 13 as its inlet. The blades 16 of thepaddle wheel are ofcourse so disposed as to face substantially flatwise to their directionof orbital motion.

The paddle wheel is connected with the engine by a transmission (notshown) whereby the paddle wheel is rotated in the direction to carry itsblades downwardly and rearwardly as they move betweenthe auger flights,and the snow that they receive there is carried rearwardly around thebottom of the chamber 14 and is thence expelled upwardly through anoutlet 18 in the top of the chamber that opens tov a spout 19. Snow isdischarged through the outlet with a substantial upward momentum, andthe spout guides it into a desired trajectory, the spout beingadjustable in a known manner to control the obliquely upward angle ofsnow discharge and the direction of such discharge.

It is a feature of the paddle wheel impeller of this invention that itsblades 16 are of resiliently flexible material. Rubber or a rubber-likematerial has been found very satisfactory. The blades are generallyrectangular in outline and are relatively thick. For example, a rubberblade that is about 3% in. wide (measured parallel to the paddle wheelaxis) and 3% in. long should be about l/2 in. thick to give it thenecessary stiffness.

As shown, the paddle wheel has three blades, and its body portioncomprises a simple triangular plate 20, to the center of which a tubularhub 21 is welded.

At each apex of the triangular plate there is welded a small securementplate 22, disposed normal to the plane of the triangular plate. Eachsecurement plate flatwise overlies the front face of one of the bladesin a zone adjacent to the radially inner edge of the blade, and itcooperates with a rigid backing member 23 in securing the blade to theplate 20.

Each backing member extends across the major portion of the width of theblade. It has a flat radially inner portion 25 that flatwise overliesthe rear face of the blade opposite the securement plate 22, and has aradially outer portion 26 that curves rearwardly away from the normalplane of the rear face of the blade and performs the very importantfunction of controlling the flexing of the blade.

Each blade has a pair of holes therethrough near its radially inneredge. These are aligned with corresponding holes in its securement plate22 and in the flat portion 25 of its backing member 23; and throughthese aligned holes pass cap screws 27 that are secured by lock nuts 28.In this manner each blade is held in place on the triangular body,clamped between its secure ment plate and the flat part of its backingmember.

Because each blade is thus clamped only along its radially innermarginal edge portion, the major part of the blade is free to flexrearwardly if a hard article such as a stick or a stone comes between itand a wall of the chamber 14. Such flexing of the blades of courseprevents the paddle wheel from being jammed by such objects; but if theblade were not controlled in its flexing, it would bend sharply in azone adjacent to the members between which it is clamped, with theresult that it would crack and eventually fail, as hereinaboveexplained.

The curved radially outer portion 26 of the rigid backing member definesthe minimum radius of curvature to which the blades can be forced in itsflexing, as illustrated by the broken lines in FIG. 2. As herein shown,the radially outermost surface of this portion of the backing membercorresponds to a longitudinal segment of a cylinder which is tangent tothe normal plane of the rear face of the backing member and which hasits axis a distance behind the blade and parallel to the axis ofrotation of the paddle wheel. The radius of curvature of this surface isof course large enough to insure that no portion of the blade materialwill be stressed excessively when the blade is flexed to the maximumextent that the backing member permits.

It will be understood that the radially outer portion of the backingmember need not have a curve of uniform radius, such as is here shownbut its curve should be a smooth one and should be tangent to the normalplane of the rear face of the blade, and of course every part of itscurvature should have a radius large enough to insure against excessiveflexing of the blade. It is also important that the curved portion ofthe backing member extend through a sufficient number of degrees of arcto accommodate the maximum deflection to which the blade might besubjected.

From the foregoing description taken with the accompanying drawings itwill be apparent that this invention provides a very simple andextremely durable paddle wheel impeller for nonhomogeneous materials,capable of yielding in the presence of chunks of hard material and thuswell adapted to serve as the second stage impeller of a two stage snowblower.

Those skilled in the art will appreciate that the invention can beembodied in forms other than as herein disclosed for purposes ofillustration.

The invention is defined by the following claims. We claim: l. A paddlewheel impeller for a two-stage .snow

. blower or the like, comprising:

A. a triangular plate; B. a cylindrical hub secured to the center ofsaid plate with its axis normal to the surfaces of the plate, to mountthe plate for edgewise rotation in one direction; C. three rigidsecurement plates, each bonded along one of its surfaces to an edgeportion of the triangular plate, one near each apex thereof, saidsecurement plates being normal to the surfaces of the triangular plateand facing substantially flatwise to its direction of rotation; D. threenormallyflat resiliently flexible blades, each having a front face and arear face, and each having a radially inner portion at which its frontface flatwise overlies one of said securement plates and an outerportion projecting radially beyond its securement plate a substantialdistance; E. three rigid backing members, one for each blade,

each backing member having I. a radially inner flat portion whichflatwise overlies the rear face of said radially inner portion of theblade, and Y 2. a radially outer portion which is curved rearwardly awayfrom the plane of the rear face of the outer portion of the blade in anarc of substantially larger radius than the smallest radius about whichthe blade is capable of flexing, and which defines the sharpestcurvature that the blade can assume in its rearward flexing; and

F. screw fastening means extending through the inner portion of eachblade and of its backing member and confining them in flatwisesuperimposed relation to one another and the securement plate.

2. A paddle wheel impeller for effecting movement of a material such assnow that is normally soft and substantially homogeneous but may bemixed with chunks of harder material, said paddle wheel impeller being rtatable in one direction about a defined axis and comprising:

A. a flat body having edges of uniform length that meet at equiangularcorners;

B. a cylindrical hub secured to the body plate at its center, with itsaxis normal to the surfaces of the body plate, for mounting the bodyplate for edgewise rotation in said direction;

C. a plurality of normally flat resiliently flexible blades, one foreach edge of the body plate;

D. a pair of clamping members for each blade,

1. each of said clamping members having a flat securement portion of ashape and size to overlie one face of only a portion of theblade,'leaving another portion of the blade projecting edgewisetherebeyond in one direction, and I 2. one of said clamping membershaving another portion which is curved out of the plane of itssecurement portion in an arc of substantially larger radius than thesmallest radius about which the blade is capable of flexing;

E. fastening means securing said clamping members for each blade totheir blade with the flat securement portions of the clamping membersflatwise overlying opposite faces of said one portion of the blade andwith said other portion of said one clamping member opposing but curvedaway from said other portion of the blade to define the sharpestcurvature that said other portion of the blade can assume in its flexingin one direction; and

F. means bonding to each of the edges of the body plate, near a cornerthereof, one of the clamping members for each blade, with the securementportion of the bonded clamping member flatwise overlying the edge of thebody plate and normal to the body plate, to dispose the bladesubstantially flatwise to the direction of rotation of the body plate,and with said other portion of said one clamping member curved away fromthe direction of body plate rotation.

and t UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No- 31805. 01 Dated Avril 23. 197

Inventor(s) Igor Kamlukin It is certified thatetror appears in theabove-identified. patent hat said Letters Patent are hereby corrected asshown below:

Column 6 line 3 (Claim 2 para A line 1) v the word "flat" should bedeleted.

Signed "and sealed this lOth day ofSeptember 197 (SEAL) Attest: v M C M-G N, R, T c. MARSHALL DANN Attesting Officer Commissioner of Patents RP041150 T T uscm m-oc scan-v05 1* ms. cove-min" mums cum: um o-su-m

1. A paddle wheel impeller for a two-stage snow blower or the like,comprising: A. a triangular plate; B. a cylindrical hub secured to thecenter of said plate with its axis normal to the surfaces of the plate,to mount the plate for edgewise rotation in one direction; C. threerigid securement plates, each bonded along one of its surfaces to anedge portion of the triangular plate, one near each apex thereof, saidsecurement plates being normal to the surfaces of the triangular plateand facing substantially flatwise to its direction of rotation; D. threenormally flat resiliently flexible blades, each having a front face anda rear face, and each having a radially inner portion at which its frontface flatwise overlies one of said securement plates and an outerportion projecting radially beyond its securement plate a substantialdistance; E. three rigid backing members, One for each blade, eachbacking member having
 1. a radially inner flat portion which flatwiseoverlies the rear face of said radially inner portion of the blade, and2. a radially outer portion which is curved rearwardly away from theplane of the rear face of the outer portion of the blade in an arc ofsubstantially larger radius than the smallest radius about which theblade is capable of flexing, and which defines the sharpest curvaturethat the blade can assume in its rearward flexing; and F. screwfastening means extending through the inner portion of each blade and ofits backing member and confining them in flatwise superimposed relationto one another and the securement plate.
 2. a radially outer portionwhich is curved rearwardly away from the plane of the rear face of theouter portion of the blade in an arc of substantially larger radius thanthe smallest radius about which the blade is capable of flexing, andwhich defines the sharpest curvature that the blade can assume in itsrearward flexing; and F. screw fastening means extending through theinner portion of each blade and of its backing member and confining themin flatwise superimposed relation to one another and the securementplate.
 2. A paddle wheel impeller for effecting movement of a materialsuch as snow that is normally soft and substantially homogeneous but maybe mixed with chunks of harder material, said paddle wheel impellerbeing rotatable in one direction about a defined axis and comprising: A.a flat body having edges of uniform length that meet at equiangularcorners; B. a cylindrical hub secured to the body plate at its center,with its axis normal to the surfaces of the body plate, for mounting thebody plate for edgewise rotation in said direction; C. a plurality ofnormally flat resiliently flexible blades, one for each edge of the bodyplate; D. a pair of clamping members for each blade,
 2. one of saidclamping members having another portion which is curved out of the planeof its securement portion in an arc of substantially larger radius thanthe smallest radius about which the blade is capable of flexing; E.fastening means securing said clamping members for each blade to theirblade with the flat securement portions of the clamping members flatwiseoverlying opposite faces of said one portion of the blade and with saidother portion of said one clamping member opposing but curved away fromsaid other portion of the blade to define the sharpest curvature thatsaid other portion of the blade can assume in its flexing in onedirection; and F. means bonding to each of the edges of the body plate,near a corner thereof, one of the clamping members for each blade, withthe securement portion of the bonded clamping member flatwise overlyingthe edge of the body plate and normal to the body plate, to dispose theblade substantially flatwise to the direction of rotation of the bodyplate, and with said other portion of said one clamping member curvedaway from the direction of body plate rotation.